It is well known that printing units such as adding machines operate with the use of paper tape that is fed through the unit, the paper tape being unwound from a roll of the paper tape with the help of automatic mechanisms in the unit. In operation, the printing unit will print on one side of the paper tape, and then index the printed tape outwardly while drawing further tape from the source. It is common experience that the printed paper tape produced by the printing unit forms a long, uncontrolled and cumbersome strip which is generally ripped off and discarded by the operator.
There are three significant disadvantages to this prior art procedure in regard to the paper tape. In the first place, it is difficult and cumbersome to store the individually ripped-off pieces of paper tape in the event that the operator wishes to keep a good record of the material printed on the tape. Secondly, conventional systems such as the printing system described above make use of only one side of the paper tape, because the machine is adapted to print on only one side of the tape. Thirdly, the machine's paper roll holder usually consists of arms and an axle. In the event of this breaking, there is no simple, inexpensive method for rendering the machine operative again.
It would be of advantage to provide a system by which the tape could be printed on both sides, and the attainment of this advantage is one of the aims of the present invention.